A computer network is a collection of interconnected computing devices that exchange data and share resources. In a packet-based network the computing devices communicate data by dividing the data into small blocks called packets. Certain devices within the network, such as routers, maintain routing information that describes routes through the network. In this way, the packets may be individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form.
A virtual private network (VPN) may be used to extend two or more remote layer 2 (L2) customer networks through an intermediate layer 3 (L3) network (usually referred to as a provider network), such as the Internet, in a transparent manner, i.e., as if the network does not exist. In particular, the VPN transports layer two (L2) communications, such as “frames,” between customer networks via the network. In a typical configuration, routers coupled to the customer networks define label switched paths (LSPs) through the intermediate network in accordance with one or more multiprotocol label switching (MPLS) protocols.
In some cases, a VPN may be supported across multiple autonomous systems (ASes) within two or more service provider (SP) networks. Each AS may comprise an individual network including at least one border device that communicates with routers in other autonomous systems, and each AS may be owned or managed by a different service provider. The border device typically uses a Border Gateway Protocol (“BGP”) (i.e., an L3 routing protocol), such as an external BGP (“eBGP”) to advertise locally learned addresses to other border devices in other autonomous systems and an internal BGP (“iBGP”) to advertise learned addresses within the autonomous system.
Customer devices may connect to services provided by data centers. Data centers may host infrastructure equipment, that provide customer devices with network services. For example, data centers may host web services for enterprises and end users. Virtualized data centers are becoming a core foundation of the modern information technology (IT) infrastructure. In particular, modern data centers have extensively utilized virtualized environments in which virtual hosts, such virtual machines or containers, are deployed and executed on an underlying compute platform of physical computing devices. In some instances, customer devices may connect to data centers over multiple autonomous systems of two or more service providers.